Search results for "Classical"
showing 10 items of 2294 documents
Les Pouvoirs de Galatée
2021
International audience; No abstract.
Quasi-rational solutions of the NLS equation and rogue waves
2010
We degenerate solutions of the NLS equation from the general formulation in terms of theta functions to get quasi-rational solutions of NLS equations. For this we establish a link between Fredholm determinants and Wronskians. We give solutions of the NLS equation as a quotient of two wronskian determinants. In the limit when some parameter goes to $0$, we recover Akhmediev's solutions given recently It gives a new approach to get the well known rogue waves.
Nonlocal dispersion anomalies of Dyakonov-like surface waves at hyperbolic media interfaces
2016
Dyakonov-like surface waves (DSWs) propagating obliquely on an anisotropic nanostructure have been theoretically proved in a few cases including 2D photonic crystals and metal-insulator (MI) layered metamaterials. Up to now, the long-wavelength approximation has been employed in order to obtain effective parameters to be introduced in the Dyakonov equation, which is largely restricted to material inhomogeneities of a few nanometers when including metallic elements. Here, we explore DSWs propagating obliquely at the interface between an insulator and a hyperbolic metamaterial, the latter consisting of a 1D MI bandgap grating using realistic slab sizes. We found unexpected favorable condition…
Capillary Rise in Nanopores: Molecular Dynamics Evidence for the Lucas-Washburn Equation
2007
When a capillary is inserted into a liquid, the liquid will rapidly flow into it. This phenomenon, well studied and understood on the macroscale, is investigated by Molecular Dynamics simulations for coarse-grained models of nanotubes. Both a simple Lennard-Jones fluid and a model for a polymer melt are considered. In both cases after a transient period (of a few nanoseconds) the meniscus rises according to a $\sqrt{\textrm{time}}$-law. For the polymer melt, however, we find that the capillary flow exhibits a slip length $\delta$, comparable in size with the nanotube radius $R$. We show that a consistent description of the imbibition process in nanotubes is only possible upon modification o…
The generalized plane piezoelectric problem: Theoretical formulation and application to heterostructure nanowires
2016
We present a systematic methodology for the reformulation of a broad class of three-dimensional (3D) piezoelectric problems into a two-dimensional (2D) mathematical form. The sole underlying hypothesis is that the system geometry and material properties as well as the applied loads (forces and charges) and boundary conditions are translationally invariant along some direction. This class of problems is commonly denoted here as the generalized plane piezoelectric (GPP) problem. The first advantage of the generalized plane problems is that they are more manageable from both analytical and computational points of view. Moreover, they are flexible enough to accommodate any geometric cross secti…
Astronomiskās un dabas parādības aizvēsturē Ziemeļeiropā: atspoguļojums vēstures avotos un arheoloģiskajā materiālā
2021
Cilvēka dzīve aizvēsturē bija ļoti cieši saista ar dabu. Līdz ar pāreju uz ražotājsaimniecību vēlā akmens laikmeta beigās, bet īpaši sākot ar bronzas laikmetu, izveidojās ideoloģija, kurā centrālo vietu ieņēma Saule un ar to saistīto gadskārtu cikli. Solārā un lunārā simbolika plaši pārstāvēta Ziemeļeiropas, arī Latvijas arheoloģiskajā materiālā. Dabas un astronomiskās parādības minētas arī pirmajos rakstītajos avotos, bet to sekas – īpaši dabas katastrofu sekas, fiksējamas arī arheoloģiskajā materiālā.
Economic Theory and its History
2016
This collection of essays is a tribute to Neri Salvadori, the man and scholar, teacher and friend, whom the scientific community owes important works in the tradition of Piero Sraffa’s revival of the classical economists’ approach to the problems of value, income distribution, capital accumulation, technical progress, scarce natural resources, economic development and growth. The essays in this book have all been freshly written and contain original work with novel ideas in the areas mentioned.
Hippocampal theta activity is selectively associated with contingency detection but not discrimination in rabbit discrimination-reversal eyeblink con…
2009
The relative power of the hippocampal theta-band ( approximately 6 Hz) activity (theta ratio) is thought to reflect a distinct neural state and has been shown to affect learning rate in classical eyeblink conditioning in rabbits. We sought to determine if the theta ratio is mostly related to the detection of the contingency between the stimuli used in conditioning or also to the learning of more complex inhibitory associations when a highly demanding delay discrimination-reversal eyeblink conditioning paradigm is used. A high hippocampal theta ratio was not only associated with a fast increase in conditioned responding in general but also correlated with slow emergence of discriminative res…
Three-dimensional Hall effect accelerometer for recording head movements of freely moving laboratory animals
1991
A Hall effect device was constructed for a measurement of head movements in three spatial dimensions during classical conditioning experiments in cats. A Hall sensor was used to detect movements of a magnetic fragment floating in a small (15 x 15 mm) cube. The magnetic fragment was kept in the centre of the sealed cube with a thin coil spring which was filled with thin oil for damping excessive afteroscillations. A comparison of this device to a commercial accelerometer showed that the accuracy of the Hall device is sufficient for the movement recordings and that the device is sensitive also to slowly accelerating movements. The construction is compact and can be easily mounted, for example…
The effect of rewarding hypothalamic stimulation on behavioral and neural hippocampal responses during trace eyeblink conditioning in rabbit (Oryctol…
2005
Rabbits were trace-conditioned with a tone as a conditioned stimulus and an airpuff as an unconditioned stimulus. Electrical stimulation to the medial forebrain bundle in the lateral hypothalamus was delivered either before or after the tone-airpuff pair. The purpose of the present study was to test whether the effect of post-trial hypothalamic stimulation differed from the effect of pre-trial hypothalamic stimulation on trace conditioning in the same subjects. Additionally, hippocampal responses were measured during sessions to see if hypothalamic stimulation activated dopaminergic fibres and affected hippocampal cell functioning and thus learning. The results showed that behavioral nictit…